However, first-half profits were weighed down by £56.4 million in exceptional charges - £12.7 million in Waitrose, £21.1 million in John Lewis and £22.6 million in group – linked to it move from divisional to partnership functions across finance, personnel and IT.

The Partnership said first-half trading had been hit by “inflationary pressures” due to the weaker value of sterling and its reluctance to increase prices, and it warns margin pressures will continue into the second half.

John Lewis said it also expects to incur “higher pension accounting charges” in the second half as a result of low market interest rates at the start of the year, which together with margin pressures “will impact” overall profits.

Stripping out exceptional items, pre-tax profits in the first half were still down 4.6 per cent to £83 million, though the Partnership said this was “flattered” by property profits of £10,5 million from John Lewis and £0.9 million from Waitrose.

The John Lewis Partnership chairman, Sir Charlie Mayfield, said: “As we anticipated in our full year results statement in March, the first half of this year has seen inflationary pressures driven by exchange rates and political uncertainty.

Sir Charlie added: “Our results also reflect the acceleration of our strategy to ensure the Partnership's success in the future.

“This has included: changing the way we operate Waitrose branches, creating new flexible team structures with broader responsibilities; further changes in John Lewis to adapt the business for the future; and moving from divisional to Partnership functions across Finance, Personnel and IT.

“As a result, we incurred exceptional costs of £56.4 million.

“Given the key role our Partners play, we are very focussed on managing the risk of these changes carefully.”

Looking ahead, Sir Charlie said the Partnership's sales growth continued into the first few weeks of the second half as the group prepares to enter its “all-important seasonal peak, but added: “We expect the headwinds that have dampened consumer demand and put pressure on margins to continue into next year.